

You probably experienced connection loss. This has happened to me before. Your connection to the server went bad, you waited for his time to run out. Since you had no connection to the server, you didn't know that he had actually moved. When time runs out, your computer waits for the server to tell it that your opponent lost on time, but of course this doesn't happen. You log out, the server thinks you disconnected, and you lose on time. Sad story, really :(